Electric Charge & Circuits Flashcards
what is charge
an imbalance of protons & electrons
what is voltage
pressure caused by a separation of the charges e.g. attaching a wire to the +ve / -ve terminals of a battery
what is another term for voltage
electromotive force
what is current & what is it measured in
- rate of flow of charge
- Amps
what is resistance
a barrier to the flow of charge
what is the relationship between amps and coulombs
A = Q/T = C/S
what is ohm’s law
V = IR
where I = current (A) and R = resistance (ohm’s)
where does current originate in a battery
-ve terminal
what do batteries, resistors, loads/lightbulbs, switches, variable resistors, ammeters and voltmeters look like
notes
what are series circuits
circuits where current passes through every part of the circuit once
what are features of series circuits
R = sum(Ri)
I = V/R(sum)
current depends on total resistance
what are parallel circuits
circuits where current can be split evenly
what are features of parallel circuits
R = (1/Ri + …+ 1/Rn)^-1
I,n = V/R,n
I(sum) = (I1+…+In)
what is capacitance
capacitors can store charge to then transfer it to another system when connected
what is the formula for capcitance
Q = CV
where C = capacitance in Fardays, Q = charge, V = voltage
what does 1F = in Coulombs
96500 C
how does a positive charge electric field look
notes
how does a -ve charge electric field look
notes
where is charge moving on charged plates
from +ve –> -ve side
what is the formula for energy from a field
E = KQ/r^2
where K = constant, Q = charge, r = distance
same relationships as gravitational fields
what is the formula for force of an energy field
F = KQ1Q2/r^2
what is the voltage for plates
V = E*d
where E is field energy & d is distance
